This program simulates thousands of balls, and the collisions among them and the borders of the screen.
Spatial partitioning is applied, so if ran in release mode, it should be able to handle around
20,000 balls. The ball collisions are elastic collisions, so no momentums will be lost.

You can drag a ball and force the balls to collide themselves.
Also the arrow keys can simulate the gravity.
The key '1' will shift the ball renderers, which renders the ball differently.
Lastly, the key 's' will stop all the balls.

1st renderer: It will render the balls with the information the balls have(Color and size).
2nd renderer: It will render the balls with their momentum(mass * velocity).
3rd renderer: It will render the balls that are going to the x direction(to the right).

Feel free to develop more with these codes.

Citation: Ben Arnold(MakingGamesWithBen)'s youtube tutorials.